Hi There, In the process of doing alot of work to the 68. (NOS,Line Lock,Stereo,Guages,etc,,,,,) Anyway as I add more electronics I seem to be pulling my hair out every time trying to find a source of "Ignition on Power." Anyway I am no wiring guru but was wondering if there is a way to wire up some sort of Panel of circuits that are hot when the ignition is "hot", that way whenever I add a new toy I could just "plug" in rather than splice in somewhere else...If so How would I wire that? I would like to do one up front somewhere as well as one in the trunk (Is there somewhere to get power back there or would I have to run a line from up front??

Thanks

It's do-able, but potentially messy. As you add all these new things, you're increasing the load on that one lil 12 guage wire from the horn relay to the fuseblock, and if you add enough stuff, you'll eventually cause an overload.

What I'd do is get a relay (30 amp or so??) and a terminal block, maybe from radio shack? Find a good place to attach them, wire the load supply for the relay to the horn relay, splice off the coil wire (before any inline resistance) and use that to trigger the relay. Run the relay output to the terminal block, and tap off new wires from there to any devices you need to power.

Hi Jim, THANKS for the reply...I'll give that a shot. Just out of curiosity what does a Relay do...I know what one is just not sure what it actually does...IE how is that different than just pulling power from the horn to the terminal??

Also, what about a heavier guage wire directly from the battery to a termianl block. With some kind of inline switch. Would protect from overload and offer a hidden switch to disable the car if I ran the coil wire from it.

Thanks

I seem to be pulling my hair out every time trying to find a source of "Ignition on Power." Anyway I am no wiring guru but was wondering if there is a way to wire up some sort of Panel of circuits that are hot when the ignition is "hot", that way whenever I add a new toy I could just "plug" in rather than splice in somewhere else...If so How would I wire that? You need to just add a auxiliary fuse box, painless makes them
http://www.painlessperformance.com/webcatalog/cat-fuseblock.htm
If you are adding any high current items, they should be wired with their own power source, through their own relay. Heres a pic
http://www.painlessperformance.com/webcatalog/images/1098relay.jpg
It only takes a fraction of a amp to switch the relay on, which would be drawn from the original wiring. For a power source, the best place is the horn relay.

also check with www.madelectrical.com they have great relays and good phone service with questions. :)

Hi Jim, THANKS for the reply...I'll give that a shot. Just out of curiosity what does a Relay do...I know what one is just not sure what it actually does...IE how is that different than just pulling power from the horn to the terminal??

As JimM described the setup the relay only allows power to the terminal block when the ignition (key) is on, versus being hot constantly.


Also, what about a heavier guage wire directly from the battery to a termianl block. With some kind of inline switch. Would protect from overload and offer a hidden switch to disable the car if I ran the coil wire from it.

Bad idea especially if you ever have a short to ground. It will potentially fry everything connected to the terminal block and possibly start a fire, or both.

also check with www.madelectrical.com they have great relays and good phone service with questions. :)
I second this recommendation. You may pay a little more, but the customer service is excellent and they do an incredible job of explaining how your electrical system works and the proper way to modify it.

looks like this was explained a few times, but a relay is simply a remote switch. In this case, it would be "switched on" by the ignition circuit. It lets a small switch control a large amount of power.

On any early chevy with a stock type wiring harness, the best place to draw power is the horn relay. It's the closest easy connection to the power source, which is the alternator, not the battery.

Unless you're in a super hurry, I second the recommendation of looking over the MAD Electrical website for relay info and terminal block usage.

During my engine replacement which started in late June, I became his dream customer and ordered the whole power system upgrade kit. When you look over what it does, it really shows how inadequate the original wiring is for today's electronics and loads.

What you want is a secondary fuse block, not a secondary terminal block; all the electrical vendors (and J.C. Whitney) have them. They come in various sizes with multiple circuits and a fuse receptacle for each load so you can fuse each circuit correctly.
:beers:

What you want is a secondary fuse block, not a secondary terminal block; all the electrical vendors (and J.C. Whitney) have them. They come in various sizes with multiple circuits and a fuse receptacle for each load so you can fuse each circuit correctly.
:beers:

Now there's a good idea. My bad for neglecting to mention proper fusing in my original suggestion. An ignition switched relay powering a secondary fuseblock is just the ticket.